Currently, the handheld device market is fiercely competitive. In addition to price, the handheld device manufacturers also give more reliance on the perfect functions and good performance of the products. To a large extent, the performance of a handheld device is represented by its power consumption.
Usually, the research on managing the power consumption of handheld devices is concentrated on the design for hardware power consumption, for example: a design for power supply, a design for different voltage and a design for sleep and deep sleep modes. These designs for hardware power consumption have obvious effect, taking the design for power supply partitions for example, the current is measured through opening or closing every partition after projecting the chip, so as to calculate the power consumption of each partition. During the application, the power supply of an unused partition is switched off and the power supply of a used partition is switched on, thereby the goal of saving power consumption is realized. For another example: in the design for sleep and deep sleep modes, when the handheld device does not need to use the core, but needs to use the peripherals, it will enter a sleep mode; when the handheld device does not need to use both the core and the peripherals, it will enter a deep sleep mode. This design can also achieve the goal of saving power consumption.
Nevertheless, the foregoing power consumption management focuses on the switching between a working state and a pause state of the handheld device and does not separately consider the power consumption of the handheld device is different when the chip of the handheld device is on different operating frequencies at the working state.
The formula for calculating the power consumption of the chip of the handheld device is: Pt=Fre×Pw; where Pt (unit: mw) is the total power of the chip; Fre (unit: MHz) is an operating frequency of the chip; Pw (unit: mw/MHz) is the power consumption indicator of the chip.
Before projecting a chip, a low Pw value is determined typically through a hardware power consumption management policy, simplified design for digital logic and process selection. After projecting the chip, the management of power consumption is achieved mainly through controlling Fre when using the chip, i.e.: a Fre is set to make the power consumption of the handheld device low when the handheld device is in a normal working state and is operating on this Fre.
However, regarding each existing handheld device, its frequency when all functions of the handheld device are operated is set as a normal operating frequency. Even if the handheld device only uses a simple function, such as checking the time, playing an old school snake game or reading a short message, it will still run at the set operating frequency. Moreover, in the time after the operated function is achieved, the system will still run in an idle state of the operating frequency. Consequently, the fewer the functions of the handheld device are used and the longer the time of idle state is, the more the energy waste will be caused.